B→ππ, new physics in B→πK, and implications for rare K and B decays -: art. no. 101804

The measured B-->pipi,piK branching ratios (BRs) exhibit puzzling patterns. We point out that the B-->pipi hierarchy can be nicely accommodated in the standard model (SM) through nonfactorizable hadronic interference effects, whereas the B-->piK system may indicate new physics (NP) in the electroweak (EW) penguin sector. Using the B-->pipi data and the SU(3) flavor symmetry, we fix the hadronic B-->piK parameters and show that any currently observed feature of the B-->piK system can be easily explained through enhanced EW penguin diagrams with a large CP-violating NP phase. This in turn implies in particular an enhancement of the K-L-->pi(0)nu(nu) over bar rate by 1 order of magnitude, with BR(K-L-->pi(0)nu(nu) over bar)approximate to4BR(K+-->pi(+)nu(nu) over bar), BR(K-L-->pi(0)e(+)e(-))=O(10(-10)), and (sin2beta)(pinu(nu) over bar)<0. We address also other rare K and B decays and B-d-->phiK(S).